|Publication number||US7481059 B2|
|Application number||US 10/905,205|
|Publication date||Jan 27, 2009|
|Filing date||Dec 21, 2004|
|Priority date||Aug 12, 2004|
|Also published as||EP1789728A1, EP1789728A4, US20060032231, WO2006016842A1|
|Publication number||10905205, 905205, US 7481059 B2, US 7481059B2, US-B2-7481059, US7481059 B2, US7481059B2|
|Inventors||Stefan Andersson, Patrik Bäckander, Hans Falk, Klas Lindblad, Hakan Schmidt|
|Original Assignee||Volvo Aero Corporation|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (20), Classifications (9), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present application claims the benefit of U.S. Provisional Application Nos. 60/601,011 filed 12 Aug. 2004 and 60/522,205 filed 31 Aug. 2004. Said applications are incorporated herein by reference in their entireties.
The present invention relates generally to afterburners for jet engines; and more particularly, the invention relates to afterburner fuel-feed arrangements for such engines which may be exemplarily employed on aircraft.
Afterburner spraybars for jet engines are well appreciated assemblies by those persons skilled in the relevant art. An example of such spraybars is found in International Publication Number WO 2004/033966 A1 which designates the United States, and in the corresponding United States Provisional Patent Application having Application No. 60/319,601; each of which are hereby expressly incorporated by reference for purposes of disclosure.
In general, afterburner fuel spray arrangements are utilized to boost the thrust of jet engines during limited high-demand periods. Relevant to aircraft engines, such times can include, for instance, take off from the flight deck of an aircraft carrier.
The afterburner spraybars are located in the core gas flow of the jet engine, and are therefore subjected to extremely high temperatures, which can also be quite variable. This can present challenges, especially to configurations such as that shown in WO 2004/033966 A1 in which fuel pipes are directly exposed to the hot core gases behind the turbine section of the engine. Another problem with such fuel-pipe-exposed configurations is that the unsupported, relatively long length of the fuel pipes can make the assembly susceptible to eigenfrequencies (natural or harmonic frequencies) falling within engine range frequencies which is also viewed as detrimental.
For these reasons, it is generally known to provide protective heat shield structures for such afterburner fuel pipes, and even to distribute cooling bypass air thereto. One particular example is found in U.S. Pat. No. 5,297,391 wherein a fuel distributing pipe 52 is preceded (with respect to core gas flow) by a shielding tubular enclosure 54. Through the illustrations of FIGS. 4-6 of the '391 patent, however, it is clear that the overall length of the fuel pipe 52 remains substantially unbraced with regard to the enclosure 54. In fact, as depicted in FIG. 5 of the '391 patent, it is clear that a slit 70 must be maintained therebetween in order for cooling air to pass therethrough. Even though it could be said that it appears from FIG. 6 that a distal or bottom end of the fuel pipe could be anchored in a wall end 66 of the enclosure 54, it is not represented that the predominantly unsupported length of the fuel pipe 52 is braced against assuming harmonic oscillation, with the engine. This detrimental performance can obviously cause extreme vibration of the fuel pipe 52 and/or enclosure 54 resulting in unacceptable vibrations of, and friction and wear between, the several constituent components. Still further, each fuel pipe is individually enclosed, and no fuel pipes are arranged adjacent or abreast to one another in a crosswise orientation to the engine's core gas flow as defined by the present invention, and as will be described in greater detail hereinbelow. These individual assemblies disclosed in the '391 patent are not only costly, but their required frequency of radial distribution within the core gas flow can compromise the throughput of the engine.
For these reasons, as well as others that will become evident to those persons skilled in the art from the descriptive disclosure provided herein, the present invention has been developed to address these problems and provide additional benefits to users.
As disclosed herein, the present invention is described with respect to three primary embodiments: (1) the afterburner fuel-feed arrangement alone; (2) the arrangement installed in a turbo-combustion engine; and (3) the arrangement installed in a turbo-combustion engine and mounted on an aircraft. In that the commonality between these several embodiments is the spraybar of the afterburner fuel-feed arrangement, and the other components of the developed embodiments are generally known, at least as utilized in the present disclosure, the invention is summarized on the basis of the spraybar.
Therefore, in one embodiment, the present invention takes the form of an afterburner fuel-feed arrangement comprising (including, but not necessarily limited to) an elongate fuel spraybar for distributing fuel to the afterburner section of a turbo-combustion engine. The spraybar has a longitudinal axis and includes a fuel-receiving spray head in fluid communication with a plurality of elongate fuel pipes surrounded by an elongate, aerodynamic-shaped shroud. The spray head is configured to be mounted in a casing of a turbo-combustion engine (which is contemplated to include both turbo-jet and turbo-fan engine configurations) and thereby project the surrounded fuel pipes into an interior through-core of the engine in cross-wise orientation to a core gas flow therein to establish an installed configuration of the spraybar.
In this embodiment, the shroud has an interior lateral sidewall that includes a pipe-receiving portion. The pipe-receiving portion is configured to abuttingly engage a corresponding shroud-engaging portion of an exterior surface of one of the plurality of elongate fuel pipes. The pipe-receiving portion is configured to substantially maintain the position of a fuel pipe, received therein, relative to the shroud. In this manner, the fuel pipes are supported along their length, and when the pipes are abuttingly engaged with the shroud, the thereby braced configuration is stiffened which raises the eigenfrequencies of the assembly (arrangement) into ranges higher than those of the incorporating engine. Each such feature serves and functions to minimize vibration, reduce wear, and increase operational life of the elongate fuel spraybar assembly.
In a further development (variation), the shroud has an elliptically tubular cross-sectional shape, taken perpendicularly to the longitudinal axis of the spraybar, along a predominance of a length of the shroud. Furthermore, the elliptical cross-sectional shape defines a long and short cross-axis of the shroud, the long cross-axis of the shroud being substantially aligned, in a preferred installed configuration, with a direction of core gas flow of the engine.
In an optional development, at least two of the several elongate fuel pipes are arranged adjacent and substantially parallel to one another, and with a longitudinal axis of each perpendicularly intersecting the short cross-axis of the shroud. As may be best appreciated in
In a complementary development, the shroud and all of the elongate fuel pipes have a longitudinal axis oriented substantially parallel to the longitudinal axis of spraybar.
As a further optional complement, the two elongate fuel pipes are adjacently and abuttingly arranged one to the other, and the so paired fuel pipes are in abutting contact with opposite interior lateral sidewalls of the shroud. In this manner, the elongate fuel pipes constitute a brace in the shroud against bending moments about the long cross-axes of the shroud.
As intimated above, another beneficial feature of the present invention is that accordingly configured spraybars have eigenfrequencies greater than eigenfrequencies of receiving engines thereof.
In a further development, the shroud further includes multiple (a plurality of) pipe-receiving portions, each of which includes an elongate recessed portion (i.e., a groove) flanked on each of two lateral sides thereof by an elongate raised-ridge portion. It is this configuration that presents the “wave” or fluted interior surface of the shroud.
In one example, a tight friction-fit exists between each of the plurality of pipe-receiving portions and a respective fuel pipe received therein when the spraybar is in an inactive state without fuel being fed through the fuel pipes (see
It is preferred that each of the fuel pipes be tubular, and more preferably cylindrical in shape (having a circular cross-section) and that each respective pipe-receiving portion of the shroud be concavely configured (e.g., as a groove) and sized to establish an abutting conformance fit with a respective fuel pipe received therein when in the inactive state. In this manner, relative motion (or resistance thereto) between the fuel pipes and shroud provides mechanical damping to the spraybar and thereby decreases stress caused by vibrations.
Conversely, but in a complementary manner, in the active state in which the fuel pipes are being cooled (but the shroud is obviously still being heated by the core gas flow), a spaced-apart, but trapped configuration is established for the cylindrical fuel pipes received within the recessed portion (bounded by the raised-ridge portions) of the pipe receiving configuration at the interior lateral wall of the shroud. It should be appreciated that in this configuration a gap space can at least intermittently exist between the fuel pipes and shroud. Benefits that are derived therefrom are that the transfer of heat (given the buffering air gap) between the pipes and shroud is drastically reduced, and that the thermal stress of the shroud is also reduced.
Because of the fluted configuration presented by the pipe receiving portion(s) on the interior lateral sidewall(s) of the shroud, these receiving portions, and particularly the raised-ridge portions, brace against bending moments about long cross-axes of the shroud.
As may be best appreciated in
In still a further development of the invention, the long cross-axis of the shroud (see
In yet a further development, a cooling air inlet opening is provided in the spraybar for receiving relatively cool engine bypass air into an interior space of the shroud at a location proximate a head-end of the spraybar. At a distal end of the spraybar, a cooling air outlet opening is provided for exhausting cooling air therefrom. As may be best appreciated from
As may be further appreciated from
Due to the preferred orientation of the spraybar relative to the core gas flow as depicted at least in
Several beneficial features have been described hereinabove regarding the presently disclosed invention(s). It should be appreciated that these observations are not exhaustive, and further advantages and benefits will become obvious to those persons skilled in the art in view of the present disclosure. Still further, the embodiment and examples described herein should not be considered as limiting, but are provided to assist persons skilled in the art to implement the inventions, but the meets and bounds of which are delimited exclusively by the patented claims.
Exemplary embodiments of the present invention are depicted in the accompanying drawings; the primary and unique common component being the configuration and orientation of an elongate fuel spraybar 28 for a turbo-combustion engine 12, which is contemplated to take the form of either a turbo-jet or turbo-fan configuration.
An afterburner fuel-feed arrangement 26 is shown generally interposed between the turbine and afterburner sections 23, 24, and ahead of a flame holder 21 supported on flame holder struts 22. In
It may be further appreciated in
The radial section view of
The fuel pipe 38 includes fuel outlets 39, exemplarily shown in
It should also be mentioned that
The open area 90 of the air outlet 88 is illustrated in
As intimated hereinabove,
The spray head 34 is generally cylindrically shaped, while the shroud 50 is generally elliptically shaped. Therefore, an expanding transition portion 82 is interconnectively interposed therebetween. A groove or recess 84 is shown in an interior surface of the transition portion 82 which serves as a lead-in to an elongate recessed portion 70 of the pipe receiving portion 68 of the shroud 50. Details of the interior lateral sidewall 66 of the shroud 50 are clearly depicted in
Particularly suitable methods for manufacturing the shroud 50 include cold-drawing a tube through a slotted mold or die having a shape corresponding to the desired cross-sectional shape of the shroud, including the “wave” or fluted configuration of the pipe-receiving portions 68 located on the shroud's lateral sidewall 66. Benefits of such manufacture includes the production of a relatively rigid shroud having high thermal strength. As an alternative, it is also contemplated that the shroud 50 may be produced by extrusion methods.
It will be appreciated by those persons skilled in the art, especially when taken together with the illustrations of
One particularly preferred and exemplary embodiment of the elongate fuel spraybar 28 is illustrated in
As intimated above, the described embodiments of the present invention are disclosed for illustration purposes of exemplary implementations of the unique afterburner fuel-feed arrangement 26. It should be appreciated, however, that these examples are in no way limiting with respect to the afforded patent protection which is defined by the following patented claims.
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|U.S. Classification||60/761, 60/766|
|Cooperative Classification||F23R3/20, F02C7/222, F02K3/10|
|European Classification||F23R3/20, F02C7/22C, F02K3/10|
|Jan 9, 2006||AS||Assignment|
Owner name: VOLVO AERO CORPORATION, SWEDEN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ANDERSSON, STEFAN;BACKANDER, PATRIK;FALK, HANS;AND OTHERS;REEL/FRAME:016989/0589;SIGNING DATES FROM 20050103 TO 20051201
|Jun 27, 2012||FPAY||Fee payment|
Year of fee payment: 4
|Sep 9, 2016||REMI||Maintenance fee reminder mailed|